(1) Field of the Invention
The invention relates to a loads interface, particularly a loads interface of an aircraft structure with the features of the preamble of claim 1 and to applications of said loads interface with the features of the preamble of claim 8.
(2) Description of Related Art
Door fittings of an airplane door are used for mounting the door in a form locking engagement to the airplane fuselage in flight conditions. In these conditions internal pressure is acting on the door structure and said internal pressure results in concentrated pointed loads at the corresponding contact points between the door and the fuselage, which are acting partly in a radial direction, partly in a circumferential direction to the airplane's fuselage. Said door fittings are part of the primary structure of a typical airplane door. Any transfer of concentrated pointed loads from the door leads to a multi-axial loading state at the door fittings.
The document U.S. Pat. No. 5,667,169 A discloses a door system for a passenger airplane with a bearing and guiding device which operates between a door leaf and a door frame, as well as a lifting device which is arranged between the bearing and guiding device and the door leaf. A lifting device moves the door leaf at the end of the closing movement transversely to the moving path of the guiding device with a form-locking engagement with door-frame-fixed receiving elements into the completely closed position and, at the start of the opening operation, in the opposite lifting direction out of the form-locking engagement. Any specific details of connecting the door fittings to the background structure taking into account principles of load transfer are not addressed.
The document U.S. Pat. No. 6,378,806 B1 discloses a door for an enclosed space under pressure, such as an aircraft cabin. Redundant door stops are secured to the door edges and cooperate with redundant frame stops secured to a door frame in an aircraft body. The door stops and the frame stops are arranged in pairs. Door fittings directly flanged to the edge member are suitable for metallic structures with isotropic material behaviour. In case of a fiber composite background structure any high fitting loads introduced perpendicularly to a laminate plane of an edge member of said state of the art would be liable to problems if there wouldn't be any metallic suspensions and/or brackets as back up.
The document FR 2 947 241 A1 discloses a frame for a door provided at an opening in an aircraft fuselage defined by a skin, said frame including an upper longitudinal stiffener and a lower longitudinal stiffener connecting two vertical substructures together, which are arranged on either side of the opening at which at least one abutment is provided for transferring the radial forces exerted by the door, characterized in that each vertical substructure includes at least three walls made of a composite material and connected together so as to form a closed and hollow profile in order to obtain a shell structure.
The document DE 10 2006 054431 A1 discloses an arrangement with reinforcement elements e.g. stringers and bulkheads, associated to a fuselage skin, and a door surrounding structure integrally or partially integrally designed and including a connecting surface facing toward a fuselage skin. The connecting surface is connectable with a support surface of the fuselage skin. The door surrounding structure exhibits a door surrounding frame dividingly provided in a circumferential direction of a fuselage structure, which is connectable in a region of a center section of a door cutout.
The document DE 102006054431 A1 discloses a door fitting for the mounting of doors and flaps to the fuselage structure and/or wing structure of an aircraft with a retaining part, which holds the bearing elements for the door or flap and with a flange, which is used for the fastening to the door structure or wing structure, the door holder and flange being formed as a single part in the form of a flat-surfaced, plate-like component. Any torque, which is typically acting on the door fitting, cannot be well compensated by this type of component.